DURABL3 coating
Three layers
The coating consists of three layers on top of the 12 μm electro-galvanizing underneath:
- silane pre-treatment layer
- 60 μm primer and
- 60 μm topcoat. The only three-layer-coated roofing screw on the market.
Design in compliance with Kingi
Choose the only legal option and avoid liability risks.
The new Building Act (751/2023) requires that the building and its fasteners withstand the intended environmental conditions. KINGI® is Europe’s only painted carbon steel roofing screw with official ETA approval (ETA-25/0267) for the severe C4 atmospheric corrosivity category – durability class high (H).
Beware of misleading CE marks
The old EAD assessment (330046-01-0602) underlying the CE marking of competing roofing screws states unambiguously that only stainless steel may be used in C2–C4 outdoor conditions.
“Fastenings screws which are intended to be used in external environments with ≥C2 corrosion according the srtandard EN ISO 12944-2 are made of stainless steel.”
So far, only KINGI® has a painted carbon steel screw approved for class C4 (H).
You can easily check which EAD assessment document the screw’s CE mark is based on from the screw’s ETA homepage – it contains a reference to the EAD cited.
Kingi Oy fought all the way to the European Commission to get a new assessment document (EAD 330046-02-0602) through, based on actual corrosion testing. By choosing KINGI®, you are making a genuinely legal choice and avoiding a situation in which the designer may be held responsible for an incorrect specification of fasteners.
Choosing the corrosion load class for a sheet metal roof
Practical guidance for the designer
The screws used on a sheet metal roof must be construction products intended for the application that comply with the requirements set by the Building Act and the Construction Products Regulation, including the roof’s corrosion load class (= climatic load class).
Also note: many sheet metal suppliers’ coating warranties become void if the corrosion resistance of the fasteners is of a lower class than that of the roofing sheet itself. Choosing the correct screw classification is not only a legal issue, but also an economic one.
The table below summarises the key requirements for different conditions.
| Class | Application and requirements |
|---|---|
| C2 | Clean rural area The use of class C2 in fixings outside a sheet metal roof requires site-specific documented justification and proof that the conditions, intended service life and selected product meet the essential technical requirements of the Building Act. |
| C3 | Outdoor conditions in Finland (minimum requirement) In outdoor conditions in Finland, the minimum requirement for the corrosion protection of sheet metal roof fixing screws is, as a starting point, at least class C3 in accordance with ISO 12944-2. |
| C4 | Roofs exposed to fossil fuels Class C4 is used on roofs exposed to fossil fuels (except gas). In short, if there is a chimney on the roof → C4. |
| C4+ | Coastal, industrial and other harsh conditions In harsher conditions, such as coastal, industrial, saline or particularly humid environments, the required level must be C4 or higher. |
Demonstrating suitability
The suitability of the fixing screws must be demonstrated by a product-specific ETA under the European Assessment Document EAD 330046-02-0602 or EAD 330046-01-0602. For the KINGI® roofing screw, this is ETA-25/0267, which is based on the new EAD 330046-02-0602 assessment document and covers class C4 (H).
How to specify KINGI® screws in plans
The KINGI® trademark may be used freely in building drawings, work specifications and other planning documents. From the perspective of liability for defects, it is advisable to specify in the plans a fastener in accordance with the Building Act and the Construction Products Regulation.
Example mention:
“KINGI® roofing screws (ETA-25/0267, C4-H) or another roofing screw whose corrosion resistance defined in the ETA assessment is at least equivalent to the corrosion resistance class of the sheet being fastened must be used for fastening the roofing sheet.”
Tested and proven durability
The designer’s responsibility ends with a correctly specified product. KINGI® offers three key features that make specification unambiguous and also make supervision easy after the roof is completed.
C4 (H) classification
Approved for the most demanding conditions
Tested and officially approved for outdoor use. Corrosion resistance in harsh urban, coastal and industrial climates C4, the highest resistance class (H).
Easy to verify
You can recognise it by the crown
Building control authorities and inspectors can see directly from the screw’s design-protected CrownD crown head that the correct and approved fastener has been used on the roof.
The right screw for the application – quick selection guide
KINGI® roofing screws are available in several lengths and diameters. The most important selection criteria according to the application:
- 25 and 32 mm: fastening roof and wall sheets from the bottom of the profile, overlapping sheet joints, fastening trim
- 65 mm: fastening roof and wall sheets from the top of the profile, fastening ridge and edge sheets
- Fastening substrate: wood or steel batten (maximum steel penetration capacity 0.7 + 0.7 mm)
The following colours are generally available directly from stock: RR33 black, RR32 dark brown, RR29 dark red, RR23 dark grey, RR21 light grey, RR20 white, RR11 spruce green and RR750 brick red. In addition, they can be ordered in all RR or RAL colours.
Make your work easier – download all the necessary documents
The designer’s material package contains all of KINGI®’s official documents in one place. You can download them individually below or order the entire package to your email.
DoP
Declaration of Performance
The official Declaration of Performance required by the Construction Products Regulation (CPR 305/2011).
ETA
European Technical Assessment
ETA-25/0267. Confirms the suitability of KINGI® for the C4 (H) atmospheric corrosivity category and other technical requirements.
EAD
Assessment document
EAD 330046-02-0602. New European assessment document for roofing screws (published on 19 December 2025).
